1. Field of the Invention
The invention relates to the field of sights for manually aiming articles such as projectile weapons, especially handguns, rifles and similar firearms. The invention is also useful for other aiming functions involving sighting along two alignable elements or sights that are attached to an article and spaced from one another to permit manual alignment of the article to a desired orientation by aligning the spaced sights along viewing line to a target. The invention provides an improved sighting system which permits the user to focus primarily on the target as opposed to focusing on the sights, in that the sights are structured to produce certain visual cues that the user can perceive even while focusing on a point beyond the sights and thus allowing his or her view of the sights to become somewhat blurred.
2. Description of the Related Art
A variety of sighting devices are known for orienting devices that need to be aimed. Although the present invention is applicable to various such situations, it will be discussed primarily with respect to the problem of aiming firearms and similar weapons. Firearms and the like typically have two sights that are spaced from one another along a line substantially parallel to the path along which a projectile will be discharged by the weapon. A user holds the firearm manually so as to view over and/or through the two spaced sights toward the target, before discharging the weapon. Adjustments can be made mechanically on the sight or manually by the user, to adjust for windage and elevation. In any event the object is to align the weapon accurately to the target by viewing along a line to the target and holding the weapon along that line as defined by the spaced sights.
The state of the art of present day sights includes the open or "iron" sight, the peep sight and the scope. The typical open or iron sight is by far the most commonly used for handguns and rifles. Typically an iron sight has a front sight comprising a blade member at the extreme front or muzzle end of the weapon. The blade member comprises an opaque fin that is usually rectangular in cross section and appears to the user as a thin solid block on the top surface of the barrel in line with a longitudinal axis of the barrel.
The rear sight of an open or iron sight is disposed at the rear of the weapon, and typically comprises a planar member having an open rectangular notch extending downward from a horizontal edge at the top periphery of the planar member. The rear sight can be along the barrel or over the chamber portion of the weapon, proximate to the shooter. To aim the weapon, a shooter aligns the front sight blade with the rear sight notch. The weapon is adjusted as to elevation by setting the top edge of the front sight blade even with the top of the rear sight notch. The weapon is aligned laterally by centering the blade in the notch. The intended target should appear just against the top of the front blade. The front and rear sights are dimensioned to place the discharged projectile on the target viewed in this manner at a certain range, provided the correct sight alignment is achieved.
The rear sight is closer to the shooter than the front sight, and the target is typically a substantially greater distance away. Thus it is necessary for the shooter to choose where to focus his or her eyes. If the shooter focuses on the target, the sights will appear blurred. If the shooter focuses on the sights, the target will appear blurred. To some extent, the same problem is encountered as to whether to focus on the front sight blade or rear sight notch; however, the difference in distance from the shooter's eye to the respective sights is less than the difference from either sight to the target, especially, for example, if the sights are on a handgun held at arm's length.
Shooters can shift their focus between the sights and the target, but are taught to focus on the sights when discharging the weapon, rather than upon the target. See, for example, Basic Pistol Marksmanship Guide, US Army Marksmanship Unit (ST 23-35-2 FY 83), page 8. This is considered necessary because focusing on the sights makes it possible for the shooter to see more clearly the centering of the front sight blade in the rear sight notch and the alignment of the top edge of the blade to the top edge of the notch. The weapon is aimed generally correctly even if the target is not in focus. In comparison, if the sights are misaligned, the shooter will not accurately hit the target even if the target can be seen clearly.
Because of these limitations imposed by prior art open or iron sights, such sights are generally accurate only for targets up to a range at which the target still can be seen when focusing locally, for example up to 25 meters. After about 50 meters, accuracy declines rapidly with open sights, because the view of the target is degraded.
What is needed is a structure that relieves the need to choose whether to focus on the target or on the sights. Telescopic sights are helpful for longer distances in that cross hairs not unlike the blade and notch of an open sight can be arranged optically to appear in focus when viewing a target through the sight. However, telescopic sights are expensive and vulnerable to damage.
Various sighting devices have been proposed for improving the accuracy of open gun sights, which are inherently more durable and inexpensive than the typical scope. For example, U.S. Pat. No. 4,683,662--Kiss, Jr. discloses sighting attachments for pistols which clip on the existing front and rear sights of the pistol. The front sight attachment includes a metal clip which clips to the front sight and holds a series of interchangeable sighting pins having varying diameters and colors. Kiss further discloses a rear sighting attachment which clips on the rear blade sight and includes sight inserts each forming a generally circular sight with a sector of about 60.degree.-140.degree. removed from the top of each sight insert. When aiming, the center of the circular of the rear sight insert and the front sight pin are aligned parallel to the sighting and firing line of pistol.
U.S. Pat. No. 2,927,375--Luebkeman further discloses disposing a bead or rounded ball at the end of a barrel of a gun as a front sight and a rear "notch" sight which may be rounded, instead of rectangular.
U.S. Pat. No. 4,976,038--Mattrass discloses a sighting system for a shotgun, including a front "bead" sight member (FIG. 4).
U.S. Pat. No. 1,087,747--Evans discloses a sight intended to provide for better accuracy in elevation and lateral line accuracy for game shooting. Evans discloses a substantially rectangular front gun sight having a notch or vertical slot in the center. The shooter looks through the slot to the target. The slot is defined in a thin wall resembling the notch of a conventional rear sight, and appears to extend slightly below the bottom of the rear sight when properly aimed.
An elongated slot sight is disclosed in U.S. Pat. No. 3,777,380--Theodore. Elongated slot sights, like blade-and-notch sights, require the user to align front and rear structures. With a slot, failure to align the weapon laterally relative to the target causes the slot to appear to close. It is difficult with a slot for the user to distinguish between a slot which is almost in alignment with one that is correctly in alignment, because the difference is perceived as a difference in the slot width. A very long and narrow slot is "closed" visually more easily than a wider one. Theodore has a tapering slot with contrasting colors for the slot walls, in an effort to improve its usefulness. Nevertheless, as apparent from FIGS. 5a-5e of Theodore, the user is required as a practical matter to view and focus upon the sight more than the target.
U.S. Pat. No. 3,983,634--Erickson discloses a sunshade mountable on the forward end of the rear sight of a rear peep sight of a rifle. The sunshade prevents light shining on the forward bead sight from overwhelming a shooters view of the target.
U.S. Pat. No. 1,174,063--Frank discloses any elongated front sight having a body terminating in upwardly extending wing sections and a bottom radius. A sighting bead 8 is secured within the channel defined by the upwardly extending wing sections and bottom radius.
The prior art includes a number of variations for open sights. However, the shooter typically must focus upon the sights to determine accurate alignment. What is needed is a sight structure that provides visual cues to the shooter indicating sight alignment, that rely less for accuracy on focusing on the sight, and therefore permit the user to focus more on the target.